Sim Racing servo ffb systems : OSW & Bodnar

Sure, but like he's already said, he can't. So where does that leave him? Should he just take someones word for it that he should go for "this" or "that" motor and not ask questions about it?

 

no he shouldnt, my best advice to anyone would be to stick to the industrial grade servo systems & buy the best one they can afford
( if they have already decided they are parting with the sort of cash that gets them into that range of options)
no one will go wrong with any of the options, as general guide from this -the more expensive the system the slightly better the ffb becomes ( eg the cost of the auctual system should equate to the ffb quailty received although they are all "right up there" )

there ...couldnt be simplier

 

Right, ok, good advice so far.

Sure...

...and that's the problem. They may all be great but (as you've just confirmed) some are still better than others which i presume is why you upgraded too. The answers people like spinelli are after is not whether the more expensive ones have any improvement over cheaper ones because we have some objective data easily proving they do (e.g. claimed and reported higher peak torques, etc). The answers he seeks are more to do with how much of an improvement we're talking about and seeking out both objective and subjective data on this especially from those who own 2 or more of these high end ffb wheels and can share they're opinions on how they compare? All so that he can make the best decision possible before parting with his cash.

Have you considered the possibility that perhaps Spinelli can afford to purchase the top end model but would still prefer to purchase the option that gives him the best price to performance ratio thereby not spend more money than necessary.

It may be simple for you/some (i.e. just buy most expensive that you can afford) but others prefer and/or need to put more thought into their purchases.

 

yes

 

I have not tried too much on those classic open wheelers. Some of those cars are heavy and at high speed and sharp turns, the FFB could be very high. The transient torque could be away beyond 20Nm for sure. The price diff between the small MiGg and the big MiGg is $200 (right?). I see no reason people will stick with the small MiGg. The big MiGg torque response time is excellent (less then 3ms):
http://isiforums.net/f/attachment.php?attachmentid=16905&d=1433513336

 

Yes but then you'll have further costs so that you can drive it right? Remember the amount of current required to produce the same amount of torque is higher with bigger mige.

What does MR and ML stand for? Are the suppose to represent the rise time and fall time? If so, 11.5ms for the fall time seems overly long. I would say it looks more like half of the rise time in practice. It's only 11.5ms if your settling time to satisfy reaching steady state after the fall is less than 0.5%.

Who measured the torque response and how did they measure it exactly?

 

those are motor gain parameters: Coil Resistance and Coil Inductance, respectively. Can be adjusted....
the chart they posted is the best response curve they found under those settings.
From the white paper of OSW author by Martin Ascher. He also credited to Bernhard Berger and Dennis Reimer. I do not know who actually did those measurements.

 

Ahhh, ok. Thanks for clarifying.

Whilst 3ms sounds very good, I will say however that i'm skeptical as to whether we can even perceive a difference in ffb response below 10ms. Has anyone ever tested for the perceptible threshold of this before?

 

rFactor 2 refresh rate is 100Hz, updates every 10ms, while iRacing refresh rate is 60Hz -- updates every 17ms. So, the motor's torque response time shall less than that. If not, can one feel a diff? I bet you will if your car like the IndyCar:



One probably needs with huge dynamic torque range and fast response motor to capture inner details like this....
I am slow driver. you can imagine how this chart would look like for a much faster cornering driver.

 

I'm kinda with you now.

 

eng core updates most of physics at much high rate ~ 400Hz. but API physics (telemetry data) updates at 100Hz.

 

Well, as stated several times in this very thread, Big MiGE will only be marginally better than the small in torque output beacuse it has a smaller Torque/Current ratio. Also it needs bigger ali and additional circuitry to IONI to reach the higher figures, so the cost difference is not limited to the motor only.
If you will use the IONI 1x and the bigger MIGE you'll be disappointed by the torque output.
Torque output of the smaller MIGE is a nearly perfect match to the Kollmorgen AK52 used in the Bodnar system.
If you really need higher torque than that you should really shell out some positive money for a Kollmorgen AK53.
And about higher torque in real life I've just found this http://www.roadandtrack.com/motorsports/news/a18270/you-think-driving-an-indy-car-is-easy/.
They state that top steering force of a DW12 is to be found on turn1 of Mid-Ohio and they state 35 lb.
This translate to nearly ...guess what... 20 Nm!
I agree that peak torque in a Indycar could be higher than that but I also know they are considering power steering because of the number of broken wrists in the series.
Do a simracer really need to break his wrist when crashing the car in IMS turn1?

 

You make a good point but that's if it's 35 pounds max. If it's 35 pounds in steady state, still pretty darn high ofc. Works out to be 16kg and i just went downstairs and held 2x 9kg water bottle packs in each hand and couldn't imagine doing that for an hour and a half, lol.

 

35 lb force is about 16kgrm. So torque is about = 16 x 9.8 x0.4m (wheel diameter) ~ 63 Nm, though!
Again, they talked holding force, not burst transient forces, which could be way higher, but you do not feel that way since bursting very short time.

 

thank you for the blue graph
I like blue

 

Wheel dia is barely 270mm (maybe 260).
The lever arm is 135 so, since I have considered the force applied to one hand: 155.7N*0.135m = 21.01 Nm
If the force to be considered is 35 on one side AND 35 on the other side we have 42 Nm.
And this probably is the car that has the higher forces, since the vast majority of other cars do have power steering.

But that is not the main point.

So high forces (and, as you say, even higher transient) poses a considerable risk of wrist injuries for the Indycar pilots, go figure for the armchair simdriver!
Do we really need that risk in our hobby?

 

Torque = force x radius

So even if we use your large 40cm diameter steering wheel, equivalent torque would be 31.5Nm. But what is the effective steering wheel diameter for indy cars?

I assumed ~30cm which would make it ~24Nm.

 

I applied both hands. The art in the link states "hand" pull force so I assume one hand pull 35 lb and other hand push 35 lb.

 

No need to be snide to joe.

 

But if each hand is applying 35lb of force in the same direction, that's 70lb net force and not 35lb net force.

edit: sorry. let me re-read the link.

edit 2: ok, here it is...

I read this as him saying the net force to overcome is 35lbf.

He then goes on to say...

..which seems to reaffirm that it's 35lbf net.